Sound absorption material preparation method, sound absorption material and filling method thereof

ABSTRACT

A sound absorption material preparation method, a sound absorption material and a filling method thereof. The preparation method comprises: S1, preparing a non-foaming material slurry; S2, producing a combustible material framework and a cover-shape container, and placing the combustible material framework into the cover-shape container; S3, forming the non-foamed material slurry in the cover-shape container to form a wet formed body; S4, drying the wet formed body to form a dry formed body; and S5, calcining the dry formed body, wherein the combustible material framework is burned off during the calcining step to form connected channels with a three-dimensional structure in the sound absorption material. The preparation method is simple in operation. Connected channels with a three-dimensional structure are formed in the sound absorption material so that the sound absorption effect is improved. The sound absorption material is prepared by the preparation method, has connected channels with a three-dimensional structure therein, and has a good sound absorption effect. The filling method comprises first pre-forming the sound absorption material and then filling same into a space to be filled, so that the sound absorption material fully fills the space to be filled.

FIELD OF THE INVENTION

The present invention relates to the technical field of materialpreparation, and in particular, to a sound absorption materialpreparation method, a sound absorption material and a filling methodthereof.

BACKGROUND OF THE INVENTION

In pursuit of better sound quality, a speaker (SPK) or a speaker box(SPK BOX) has a higher and higher requirement for response frequency(f₀). However, restricted by an increasingly thin and small structureand performance characteristics of a miniature speaker, it is requiredto add a sound absorption material inside the speaker to reduce theresponse frequency thereof. At present, commonly used sound absorptionmaterials for speakers mainly comprise foamed foam, such as polyurethaneand melamine, and non-foamed sound absorption materials, such asactivated carbon and zeolite. The acoustic performance of the non-foamedsound absorption materials is better than that of the foamed soundabsorption materials. The normal state of the non-foamed soundabsorption materials is powder. Thus, considering the feasibility ofquantification and process filling, the non-foamed sound absorptionmaterials are prepared to particles first; then the particles are filledinto a rear acoustic cavity of the speaker after being packaged by apolypropylene (PP) tray box with non-woven cloth, or non-woven clothonly; or the sound absorption material particles are directly filledinto the rear acoustic cavity.

Currently, common granulation solutions of the non-foamed soundabsorption materials (such as activated carbon and zeolite) in theindustry adopt an extrusion method, a spray granulation method, aboiling granulation method or a disc rolling ball method. The particlesobtained by the above method are relatively dense and small in specificsurface area and pore volume, so that a mass transfer efficiency of anair flow inside the sound absorption particles is affected when thespeaker works, and thus a sound absorption effect is greatly reduced.Although particles with relatively uniform particle sizes and internalphysical structures can be obtained through an oil-ammonia columnforming method, an oil column forming method or other equivalentmethods, it is difficult to make full use of a filling space in the rearacoustic cavity of the speaker due to its complex structure andoccupation of a large part of the rear acoustic cavity space by apackaging part of a sound absorber. As a result, the optimization effectof the acoustic performance of speaker products is limited.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a new technicalsolution of a sound absorption material preparation method.

According to a first aspect of the present invention, there is provideda sound absorption material preparation method. The preparation methodcomprises the following steps: S1, preparing a non-foamed materialslurry, and mixing the slurry uniformly; S2, producing a combustiblematerial framework and a cover-shaped container according to a setstructure, and placing the combustible material framework in thecover-shaped container; S3, forming the non-foamed material slurry inthe cover-shaped container to form a wet formed body, and separating thewet formed body from the cover-shaped container; S4, drying the wetformed body to form a dry formed body; and S5, calcining the driedformed body, wherein the combustible material framework is burned offduring the calcining step to form connected channels with athree-dimensional structure in the sound absorption material.

Preferably, the non-foamed material slurry comprises a non-foamed powdermaterial, a binder and a pore-forming agent.

Preferably, the non-foamed powder material is one or more of naturalzeolite powder, white carbon black, activated carbon powder and amolecular sieve.

Preferably, the binder is an organic silicone sol binder.

Preferably, the combustible material framework adopts an activatedcarbon fiber material.

Another object of the present invention is to provide a sound absorptionmaterial having an excellent mass transfer efficiency and soundabsorption effect.

According to another aspect of the present invention, there is provideda sound absorption material prepared according to the preparation methodprovided by the present invention.

A yet another object of the present invention is to provide a soundabsorption material having an excellent mass transfer efficiency andsound absorption effect.

According to a yet another aspect of the present invention, there isprovided a sound absorption material made of a non-foamed material. Thesound absorption material has a set space structure in which connectedchannels with a three-dimensional structure are formed.

Preferably, the specific surface area and the density of the soundabsorption material are 150-450 m²/g and 0.3-0.7 g/cm³, respectively.

Preferably, pores are formed inside the sound absorption material,wherein the pore volume is 0.5-1.7 cm³/g, and the macropore diameter is0.1-50 μm.

In addition, a yet another object of the present invention is to providea new technical solution of a sound absorption material filling method.

According to yet another aspect of the present invention, there isprovided a sound absorption material filling method, comprising thefollowing steps: SS1, preparing a non-foamed material slurry, and mixingthe slurry uniformly; SS2, producing a combustible material frameworkand a cover-shaped container according to the structure of a space to befilled, and placing the combustible material framework in thecover-shaped container; SS3, forming the non-foamed material slurry inthe cover-shaped container to form a wet formed body, and separating thewet formed body from the cover-shaped container; SS4, drying the wetformed body to form a dry formed body; SS5, calcining the dried formedbody to obtain a sound absorption material block capable of filling thespace, wherein the combustible material framework is burned off duringthe calcining step to form connected channels with a three-dimensionalstructure in the sound absorption material block; and SS6, filling thesound absorption material block into the space to be filled.

The sound absorption material preparation method provided by the presentinvention is simple in operation and allows a set space structure, suchas a rear acoustic cavity of a speaker, to be filled with the soundabsorption material so as to maximally make use of the space of the rearacoustic cavity. As the combustible material framework is producedaccording to the set structure, the connected channels with athree-dimensional structure are formed inside the sound absorptionmaterial after the combustible material framework is burned off duringthe calcining step. A sound air flow can rapidly propagate in theconnected channels with a three-dimensional structure, so that the masstransfer efficiency of the air flow generated when the speaker productworks in the sound absorption material is improved, and the soundabsorption area of the non-foamed sound absorption material isincreased, thereby improving the sound absorption effect. In addition,the added pore-forming agent further enriches a microscopic porestructure of the sound absorption material, and friction and viscousresistance of air molecules in the sound air flow are increased, so thatthe sound absorption effect is improved. A sound absorber prepared fromthe sound absorption material relatively significantly improves theacoustic performance optimization debugging effect of the speakerproduct.

The sound absorption material provided by the present invention has aset space structure which can be designed according to the structure ofa space to be filled. The connected channels with a three-dimensionalstructure are formed in the space structure, and the sound air flowrapidly propagates in the connected channels with a three-dimensionalstructure. Thus, the mass transfer efficiency of the air flow generatedwhen the speaker product works in the sound absorption material isimproved, and thus the sound absorption effect is improved. The soundabsorption material also has a rich microscopic pore structure, and hasthe characteristics of large specific surface area and pore volume, sothat the acoustic performance optimization debugging effect of thespeaker product is relatively significantly improved.

The sound absorption material filling method provided by the presentinvention is simple in operation and high in reliability. The methodallows the space to be filled, namely a rear acoustic cavity of aspeaker, to be filled with the sound absorption material, so as tomaximally make use of the space of the rear acoustic cavity. Inaddition, the connected channels with a three-dimensional structure areformed inside the sound absorption material, so that the mass transferefficiency of the air flow generated when the speaker product works inthe sound absorption material is improved, and thus the sound absorptioneffect is improved.

The inventor of the present invention finds that in the prior art, it isdifficult to fully utilize a filling space in the rear acoustic cavityof the speaker due to its complicated structure and occupation of alarge part of the rear acoustic cavity space by a packaging part of asound absorber. In addition, an air flow channel of the sound absorptionmaterial in the prior art is simple, which affects the acousticperformance optimization effect of the speaker product. Therefore, thetechnical task to be achieved or the technical problem to be solved bythe present invention is unintentional or unanticipated for thoseskilled in the art, and thus the present invention refers to a noveltechnical solution.

Further features of the present invention and advantages thereof willbecome apparent from the following detailed description of exemplaryembodiments according to the present invention with reference to theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the description, illustrate embodiments of the present inventionand, together with the description thereof, serve to explain theprinciples of the present invention.

FIG. 1 is a structural view of a combustible material frameworkaccording to an embodiment of the present invention;

FIG. 2 is a structural view of a cover-shaped container according to anembodiment of the present invention;

FIG. 3 is an assembling view of the combustible material framework andthe cover-shaped container shown in FIGS. 1 and 2; and

FIG. 4 is a structural view of a sound absorption material according toan embodiment of the present invention.

Description of the reference numerals: 1: combustible materialframework; 2: cover-shaped container; and 4: connected channels with athree-dimensional structure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Various exemplary embodiments of the present invention will now bedescribed in detail with reference to the drawings. It should be notedthat the relative arrangement of the components and steps, the numericalexpressions, and numerical values set forth in these embodiments do notlimit the scope of the present invention unless it is specificallystated otherwise.

The following description of at least one exemplary embodiment is merelyillustrative in nature and is in no way intended to limit the invention,its application, or uses.

Techniques, methods and apparatus as known by one of ordinary skill inthe relevant art may not be discussed in detail but are intended to bepart of the description where appropriate.

In all of the examples illustrated and discussed herein, any specificvalues should be interpreted to be illustrative only and non-limiting.Thus, other examples of the exemplary embodiments could have differentvalues.

Notice that similar reference numerals and letters refer to similaritems in the following figures, and thus once an item is defined in onefigure, it is possible that it need not be further discussed in theaccompanying drawings.

Embodiment 1

The present embodiment provides a sound absorption material preparationmethod. Referring to FIGS. 1-4, the preparation method comprises thefollowing steps.

In step S1, a non-foamed material slurry is prepared and mixeduniformly. The non-foamed material slurry comprises a non-foamed powdermaterial, a binder and a pore-forming agent. Of course, a templateagent, a wet enhancing agent, a dispersant or surfactant, and the likemay be added into the slurry during preparation according to actualneeds to improve the quality of the slurry. The non-foamed powdermaterial is one or more of natural zeolite powder, white carbon black,activated carbon powder and a molecular sieve. The binder is an organicsilicone sol binder, and of course, may be selected from other binders.The prepared slurry should be mixed thoroughly. Alternatively, aquantitative dripping method, an atomization adding method or otherequivalent methods are used to improve the uniformity of the slurry.

In step S2, referring to FIGS. 1-3, a combustible material framework 1and a cover-shaped container 2 are produced according to a setstructure, and the combustible material framework 1 is placed in thecover-shaped container 2. For example, the set structure is a rearacoustic cavity of a speaker, and the cover-shaped container 2 and thecombustible material framework 1 are produced according to the structureof the rear acoustic cavity. The combustible material framework 1 isburned off in a calcining step so as to form connected channels with athree-dimensional structure 4 inside the formed sound absorptionmaterial. Therefore, a sound air flow can flow out rapidly, and thus themass transfer efficiency and the sound absorption effect are improved.The combustible material framework 1 adopts an activated carbon fibermaterial, and of course, may also adopt another combustible material.

In step S3, the non-foamed material slurry is formed in the cover-shapedcontainer 2 to form a wet formed body, and the wet formed body isseparated from the cover-shaped container 2. Alternatively, the formingmethod may be an extrusion method, a spray granulation method, a boilinggranulation method, a disc rolling ball method, an oil-ammonia columnforming method, or an oil column forming method, and of course, may beother equivalent forming methods, which will not be limited in thepresent invention. The wet formed body needs to be placed for a timeafter being formed to expel bubbles inside the body. The activatedcarbon fiber material has many pores into which the slurry will permeateto finally form a fibrous shape (not shown in the figures), and finefibers mechanically vibrate to convert acoustic energy into thermalenergy. Therefore, this structure further improves the sound absorptioneffect of the sound absorption material.

In step S4, the wet formed body is dried to form a dry formed body.Further, drying is performed in air or in an inert gas, wherein thedrying temperature is 40-150° C., and the drying time is 0.5-96 hour(s).Those skilled in the art can easily understand that the lower the dryingtemperature is, the longer the drying time is; and vice versa.

In step S5, the dried formed body is roasted, and the combustiblematerial framework 1 is burned off in the calcining process so as toform the connected channels with a three-dimensional structure 4 in thesound absorption material. Further, the calcining temperature is120-850° C., the temperature rising speed is 20-120° C./h, and thecalcining time is 0.5-96 hour(s). Those skilled in the art can easilyunderstand that the lower the calcining temperature is, the longer thecalcining time is; and vice versa. Referring to FIG. 4, a soundabsorption material formed body having the connected channels with athree-dimensional structure 4 therein and having the set structure isfinally formed.

The sound absorption material preparation method provided by the presentinvention is simple in operation and allows the space of the setstructure, such as a rear acoustic cavity of a speaker, to be filledwith the sound absorption material so as to maximally make use of thespace of the rear acoustic cavity. As the combustible material framework1 is produced according to the set structure, the connected channelswith a three-dimensional structure 4 are formed inside the soundabsorption material after the combustible material framework 1 is burnedoff during the calcining step. A sound air flow can rapidly propagate inthe connected channels with a three-dimensional structure 4, so that themass transfer efficiency of the air flow generated when the speakerproduct works in the sound absorption material is improved, and thesound absorption area of the non-foamed sound absorption material isincreased, thereby improving the sound absorption effect. In addition,the added pore-forming agent further enriches the microscopic porestructure of the sound absorption material, and friction and viscousresistance of air molecules in the sound air flow are increased, so thatthe sound absorption effect is improved. A sound absorber prepared fromthe sound absorption material relatively significantly improves theacoustic performance optimization debugging effect of the speakerproduct.

Embodiment 2

The embodiment provides a sound absorption material applied to a rearacoustic cavity of a speaker. The sound absorption material is preparedby the preparation method provided by the present invention.

In particular, a non-foamed material slurry adopted in this embodimentcomprises a non-foamed powder material, a binder and a pore-formingagent. A template agent, a wet enhancing agent, a dispersant orsurfactant may be added into the slurry during preparation to improvethe quality of the slurry. The non-foamed powder material may be naturalzeolite powder, and of course, may be one or more of white carbon black,activated carbon powder and a molecular sieve. The binder is an organicsilicone sol binder. The binder is added to increase the viscosity ofthe slurry so as to form spherical particles more conveniently. A personskilled in the art can set the mass ratio of the binder according to thetype and the viscosity of the binder. The template agent plays astructural directing role. The combustible material framework 1 adoptsan activated carbon fiber material. In the present embodiment, drying isperformed in air at a drying temperature of 80° C. and with a dryingtime of 50 hours to obtain a qualified dry formed body. Duringcalcining, the temperature is 500° C., the temperature rising speed is80° C./h, and the calcining time is 60 hours. The activated carbon fibermaterial framework is burned off during calcining to form the connectedchannels with a three-dimensional structure 4. In this embodiment, thedensity, the specific surface area, the pore volume and the macroporediameter of an obtained sound absorption material formed body are 0.5g/cm³, 280 m²/g, 1.3 cm³/g and 10 μm, respectively.

In another embodiment, drying is performed in an inert gas at a dryingtemperature of 40° C. and with a drying time of 96 hours to obtain aqualified dry formed body. During calcining, the temperature is 120° C.,the temperature rising speed is 20° C./h, and the calcining time is 96hours. The activated carbon fiber material framework is burned offduring calcining to form the connected channels with a three-dimensionalstructure 4. The density, the specific surface area, the pore volume andthe macropore diameter of an obtained sound absorption material formedbody are 0.3 g/cm³, 150 m²/g, 0.5 cm³/g and 0.1 μm, respectively.

In a yet another embodiment, drying is performed in an inert gas at adrying temperature of 150° C. and with a drying time of 0.5 hour toobtain a qualified dry formed body. During calcining, the temperature is850° C., the temperature rising speed is 120° C./h, and the calciningtime is 0.5 hour. The activated carbon fiber material framework isburned off during calcining to form the connected channels with athree-dimensional structure 4. The density, the specific surface area,the pore volume and the macropore diameter of an obtained soundabsorption material formed body are 0.7 g/cm³, 450 m²/g, 1.7 cm³/g and50 μm, respectively.

Implementations not described in the present embodiment are the same asthose described in Embodiment 1.

The connected channels with a three-dimensional structure 4 are formedinside the sound absorption material provided by the present embodiment,so that the mass transfer efficiency of the air flow generated when thespeaker product works in the sound absorption material is improved, andthus the sound absorption effect is improved. The sound absorptionmaterial also has a rich microscopic pore structure, and has thecharacteristics of large specific surface area and pore volume, so thatthe acoustic performance optimization debugging effect of the speakerproduct is relatively significantly improved.

Embodiment 3

The present embodiment provides a sound absorption material made of anon-foamed material. The acoustic performance of the non-foamed materialis better than that of a foamed material. The sound absorption materialhas a set space structure in which connected channels with athree-dimensional structure 4 are formed. In particular, the specificsurface area and the density of the sound absorption material are150-450 m²/g and 0.3-0.7 g/cm³, respectively. Further, pores are formedinside the sound absorption material, wherein the pore volume is 0.5-1.7cm³/g and the macropore diameter is 0.1-50 μm.

The connected channels with a three-dimensional structure 4 are formedinside the sound absorption material provided by the present embodiment,so that the mass transfer efficiency of the air flow generated when thespeaker product works in the sound absorption material is improved, andthus the sound absorption effect is improved. The sound absorptionmaterial also has a rich microscopic pore structure, and has thecharacteristics of large specific surface area and pore volume, so thatthe acoustic performance optimization debugging effect of the speakerproduct is relatively significantly improved.

Embodiment 4

The present embodiment provides a sound absorption material fillingmethod. A space to be filled provided by this embodiment is a rearacoustic cavity of a speaker. Referring to FIGS. 1-4, the filling methodcomprises the following steps.

In step SS1, a non-foamed material slurry is prepared and mixeduniformly. The non-foamed material slurry comprises a non-foamed powdermaterial, a binder and a pore-forming agent. Of course, a templateagent, a lubrication-enhancing agent, a dispersant or surfactant, andthe like may be added into the slurry during preparation according toactual needs. The non-foamed powder material is one or more of naturalzeolite powder, white carbon black, activated carbon powder and amolecular sieve. The prepared slurry should be mixed thoroughly. Thebinder is an organic silicone sol binder, and of course, may be selectedfrom other binders.

In step SS2, a combustible material framework 1 and a cover-shapedcontainer 2 are produced according to the structure of the rear acousticcavity, and the combustible material framework 1 is placed in thecover-shaped container 2. For example, the set structure is the rearacoustic cavity of the speaker, and the cover-shaped container 2 and thecombustible material framework 1 are produced according to the structureof the rear acoustic cavity. The combustible material framework 1 isburned off in a calcining step so as to form connected channels with athree-dimensional structure 4 inside a formed sound absorption material.Therefore, a sound air flow can flow out rapidly, and thus the masstransfer efficiency and the sound absorption effect are improved. Thecombustible material framework 1 adopts an activated carbon fibermaterial, and of course, may also adopt another combustible material.

In step SS3, the non-foamed material slurry is formed in thecover-shaped container 2 to form a wet formed body, and then the wetformed body is separated from the cover-shaped container 2.Alternatively, the forming method may be an extrusion method, a spraygranulation method, a boiling granulation method, a disc rolling ballmethod, an oil-ammonia column forming method or an oil column formingmethod, and of course, may also be other equivalent forming methods. Thewet formed body needs to be placed for a time after being formed toexpel bubbles inside the body. The activated carbon fiber material hasmany pores into which the slurry will permeate to finally form a fibrousshape (not shown in the figures), and fine fibers mechanically vibrateto convert acoustic energy into thermal energy. Therefore, thisstructure further improves the sound absorption effect of the soundabsorption material.

In step SS4, the wet formed body is dried to form a dry formed body.Further, drying is performed in air or in an inert gas, wherein thedrying temperature is 40-150° C., and the drying time is 0.5-96 hour(s).

In step SS5, the dried formed body is roasted, wherein the combustiblematerial framework 1 is burned off in the calcining process so as toform the connected channels with a three-dimensional structure 4 in thesound absorption material. Further, the calcining temperature is120-850° C., the temperature rising speed is 20-120° C./h, and thecalcining time is 0.5-96 hour(s). A sound absorption material blockhaving the connected channels with a three-dimensional structure 4therein and having the set structure is finally formed.

In step SS6, the sound absorption material block is filled into thespace to be filled.

The sound absorption material filling method provided by the presentinvention is simple in operation and high in reliability. As there is noneed of polypropylene (PP) tray box or non-woven cloth for packaging,the space to be filled, namely the rear acoustic cavity of the speaker,will be filled with the sound absorption material so as to maximallymake use of the space of the rear acoustic cavity. In addition, theconnected channels with a three-dimensional structure 4 are formedinside the sound absorption material. Thus, the mass transfer efficiencyof the air flow generated when the speaker product works in the soundabsorption material is improved, and the sound absorption area of thenon-foamed sound absorption material is increased, thereby improving thesound absorption effect.

Although some specific embodiments of the present invention have beendemonstrated in detail with examples, it should be understood by aperson skilled in the art that the above examples are only intended tobe illustrative but not to limit the scope of the present invention. Itshould be understood by those skilled in the art that the aboveembodiments can be modified without departing from the scope and spiritof the present invention. The scope of the present invention is definedby the appended claims.

1-10. (canceled)
 11. A sound absorption material preparation method, comprising the following steps: S1, preparing a non-foamed material slurry, and mixing the slurry uniformly; S2, producing a combustible material framework and a cover-shaped container according to a set structure, and placing the combustible material framework in the cover-shaped container; S3, forming the non-foamed material slurry in the cover-shaped container to form a wet formed body, and separating the wet formed body from the cover-shaped container; S4, drying the wet formed body to form a dry formed body; and S5, calcining the dried formed body, wherein the combustible material framework is burned off during the calcining step to form connected channels with a three-dimensional structure in the sound absorption material.
 2. The preparation method of claim 1, wherein the non-foamed material slurry comprises a non-foamed powder material, a binder and a pore-forming agent.
 3. The preparation method of claim 2, wherein the non-foamed powder material is one or more of natural zeolite powder, white carbon black, activated carbon powder and a molecular sieve.
 4. The preparation method of claim 2, wherein the binder is an organic silicone sol binder.
 5. The preparation method of claim 1, wherein the combustible material framework adopts an activated carbon fiber material.
 6. A sound absorption material made of a non-foamed material and having a set space structure in which connected channels with a three-dimensional structure are formed.
 7. The sound absorption material of claim 6, wherein the specific surface area and the density of the sound absorption material are 150-450 m2/g and 0.3-0.7 g/cm3, respectively.
 8. The sound absorption material of claim 6, wherein pores are formed inside the sound absorption material, the pore volume being 0.5-1.7 cm3/g and the macropore diameter being 0.1-50 μm.
 9. A sound absorption material filling method, comprising the following steps: SS1, preparing a non-foamed material slurry, and mixing the slurry uniformly; SS2, producing a combustible material framework and a cover-shaped container according to the structure of a space to be filled, and placing the combustible material framework in the cover-shaped container; SS3, forming the non-foamed material slurry in the cover-shaped container to form a wet formed body, and separating the wet formed body from the cover-shaped container; SS4, drying the wet formed body to form a dry formed body; SS5, calcining the dried formed body to obtain a sound absorption material block capable of filling the space, wherein the combustible material framework is burned off during the calcining step to form connected channels with a three-dimensional structure in the sound absorption material block; and SS6, filling the sound absorption material block into the space to be filled. 